All told, in a single weekend when the calendar turned to spring, there were at least nine mass shooting events — defined by at least four people shot — across the country, as well as many more with fewer victims. It was an ominous harbinger for the warmer summer months ahead, which is typically America’s most violent time.

“We can’t endure this anymore, we just simply can’t,” said Dan Gelber, the mayor of Miami Beach, in announcing the curfew. “This isn’t your father’s, your mother’s spring break. This is something totally different.”

The surge in gun violence in the United States that began in 2020 as the pandemic set in and continued through a summer of unrest following the murder of George Floyd, shows no sign of easing. Homicides were up 30 percent that year, the largest annual recorded increase.